12 SOUTH- AFEICAN BUTTEEFLIES. 



This is especially noticeable in the Butterflies, and reaches its maximum 

 in the Moiyldtce of tropical South America, in many species of which 

 magnificent group it is difficult to comprehend how the small slender 

 thorax can contain sufiicient muscular power to work the enormous 

 wings.'^ The scales, which give to these organs their infinite variety 

 of colouring and marking, and to the Order its name (XeTr/?, scale, 

 TTTepou, wing), are planted in the membrane by slender, very minute 

 foot-stalks, and arranged so closely in transverse (not always quite 

 straight) rows, that the basal portions of the scales of each row are 

 hidden by the overlapping outer portions of those of the next row. 

 These scales are in themselves objects of remarkable beauty under the 

 microscope, their shape presenting a wonderful variety of outline, and 

 their surfaces being covered with raised longitudinal and transverse 

 lines forming a reticulation of the utmost minuteness and delicacy.^ 



The entire Order consisting of insects which live solely on fluid 

 nutriment, there is not much variation in the mouth-parts except as 

 regards the adaptation of the trunk or haustellum (modified maxillse) 

 to obtaining liquid from various sources. A certain number of Moths 

 take no food, their trunk being rudimentary ; these mostly belong to 

 the group Bornbyccs, of which the common Silkworm Moth is a familiar 

 example. The great majority of Lepidoptera, however, is in the per- 

 fect state dependent on the honey of flowers, and the trunk varies 

 greatly in length in accordance with the form of the nectar-yielding 

 blossoms frequented. The nectaries of many flowers are shallow and 

 open, and to rifle these a short haustellum suffices ; but where the 

 honey lies in a long tubular receptacle, a proportionately elongated 

 trunk is necessary. The greatest development of this kind is reached 

 in the typical S2ohingidcc, or Hawkmoths, which are thus enabled to 

 take their food on the wing, without settling, and to reach supplies 

 shut out from all other members of their Order. Thus, the haustellum 

 of the common and widely-distributed Unicorn Hawkmoth {Sphinx 

 Co7ivolvuli) is four inches long, or twice the length of the whole body ; 

 and a huge South-American ally, Amj)honyx Cluoitius, has a trunk 

 over nine inches in length. The in many ways aberrant Death's-Head 

 Hawkmoth (Acherontia Atrojjos^ — as well-known and much-dreaded in 

 South- Africa as in other parts of the world — has, on the contrary, a 

 short, stiff, broad proboscis, specially adapted for piercing the waxen 

 lid of, and abstracting the honey from the cell of the hive-bee. Again, 

 various large Nodum — such as the well-known South- African Achcea 

 Chamcelcon — are able to pierce the skins of peaches and other fruits, 



^ Thus in Morpho Iphictus the whole body is but an inch long, and the thorax less than 

 half an inch long and a quarter of an inch in breadth, while the fore-wings not only expand 

 six and a half inches from tip to tip, but are two inches broad at the outer edge, and the 

 hind-wings are each two and a half inches long and two inches broad. 



^ A favourite " test object " for some powers of the microscope has long been the scale of a 

 Morpho Butterfly, — a good glass giving clear definition of the delicate ridges on the surface 

 of the scale. 



